Graphene electrodes for single-molecule spintronics

Samenvatting

Spintronics, which aims to use the spin state of the electrons to process information, is a promising technology to supplement conventional electronics based on the control of the electrical charge of the electrons. The field is rapidly evolving into molecular spintronics where transport takes place through individual molecules advancing in miniaturization and spin-state preservation. Magnetic molecules possess intrinsic spin and therefore a spin polarized current plays a more complex role. But, under what conditions this molecular spin-state can be read, controlled or written with a spin-polarized current? The viability of molecular spintronics rest in the ability to discern and control the spin state of this magnetic molecule. I propose to investigate quantum transport through single magnetic molecules in three-terminal devices (spin transistors) made of a source and drain to bias the molecule and a gate to access different redox states. Charging the molecule combined with other external stimuli like magnetic field are expected to induce changes in the magnetic structure of the molecule that could be exploited to read and write information. Single-molecule magnets are proposed as candidate molecules.

The combination of spin-polarized currents with magnetic molecules is expected to open a new route to address and switch the molecular spin. The fabrication of such spin transistor is now hindered by technological difficulties such as the oxidation of ferrometallic contacts. I propose to implement graphene electrodes to avoid such problem. The versatility of graphene allows for combination with ferromagnetic materials enabling to address the molecular spin with spin-polarized electrons. Moreover, the stability of these electrodes at room temperature paves the way to study magnetic molecules with spin-polarized currents at ambient conditions, which is crucial for future implementation. This research will allow for the first time to control the spin state of a single molecule with a spin-polarized current.